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- SECTION 02834
-
- MODULAR CONCRETE RETAINING WALLS
-
- NOTE ** This section is based on products nationally
- manufactured under license from Anchor Wall
- Systems, Inc., which is located at the following
- address:
- NOTE ** 6101 Baker Road, Suite 201
- NOTE ** Minnetonka, MN 55345
- NOTE ** Tel: (800) 473-4452 or (612) 933-8855
- NOTE ** FAX: (612) 933-8833
- NOTE **
- NOTE ** Call for the location of the manufacturer nearest
- you.
- NOTE **
- NOTE ** "Anchor Vertica7," "Anchor Vertica Pro7," "Anchor
- Diamond7" and "Anchor Diamond Pro7" modular
- concrete wall units ensure proper alignment and
- precise set-back without need for mortar or pins
- due to their integral alignment feature.
- NOTE **
- NOTE ** SECTION 02834 - MODULAR CONCRETE RETAINING WALLS,
- Copyright 1998, The Architect's Catalog, Inc.
-
-
- PART 1 GENERAL
-
- 1.1 SECTION INCLUDES
-
- A. Modular concrete retaining wall units to the lines and
- grades designated on the construction drawings and as
- specified herein.
-
- 1.2 RELATED SECTIONS
- NOTE ** Delete any sections below not relevant to this
- project; add others as required.
-
- A. Section 02300 - Earthwork: Excavating, backfilling and
- compacting.
-
- B. Section 02900 - Planting.
-
- C. Section 02620 - Subdrainage.
-
- 1.3 UNIT PRICES
-
- A. Measurement of segmental retaining wall shall be on an
- installed square foot basis computed on the total face
- area of installed wall. Face area is from bottom of base
- course to top of wall.
-
- B. Payment for retaining wall will be made on a square foot
- basis at the Contract Unit Price.
- 1. Payment shall be considered full compensation for
- labor, materials, equipment, and testing required to
- install retaining wall in accordance with drawings
- and these specifications.
- 2. Quantities may vary from that shown on drawings,
- depending on existing topography; change to total
- quantity of wall face area will be paid or withheld
- at the Contract Unit Price.
-
- 1.4 REFERENCES
- NOTE ** Delete references from the list below that are not
- actually required by the text of the edited
- section.
-
- A. ASTM C 90 - Standard Specification for Load-Bearing
- Concrete Masonry Units.
-
- B. ASTM C 140 - Test Methods of Sampling and Testing
- Concrete Masonry Units.
-
- C. ASTM C 666 - Standard Test Method for Resistance of
- Concrete to Rapid Freezing and Thawing.
-
- D. ASTM D 448 - Standard Classification for Sizes of
- Aggregate for Road and Bridge Construction.
-
- E. ASTM D 698 - Standard Test Method for Laboratory
- Compaction Characteristics of Soil Using Standard Effort
- (12,400 ft-lbf/ft3 (600 kN-m/m3)).
-
- F. ASTM D 1557 - Test Method for Laboratory Compaction
- Characteristics of Soil Using Modified Effort (56,000 ft-
- lbf/ft3 (2,700 kN-m/m3)).
-
- 1.5 DEFINITIONS
-
- A. Backfill: Soil used as fill behind drainage aggregate
- and within the reinforced soil mass, if applicable.
-
- B. Drainage aggregate: Material used around and directly
- behind concrete wall units.
-
- C. Foundation soil: Soil mass supporting the leveling pad
- and reinforced zone of the retaining wall system.
-
- D. Geosynthetic reinforcement: Material specifically
- fabricated for use as a soil reinforcement.
-
- E. Wall fill: Free-draining aggregate material used within
- and around concrete retaining wall units.
-
- 1.6 SUBMITTALS
-
- A. Submit under provisions of Section 01300.
-
- B. Product Data: Manufacturer's printed product literature,
- including installation instructions.
-
- C. Shop Drawings: Retaining wall system design including
- wall heights, geosynthetic reinforcement and drainage
- provisions.
- 1. Prepared and signed by a registered Professional
- Engineer retained by the Installer and licensed in
- the State of wall installation.
- NOTE ** Delete the following paragraph if samples are not
- required.
-
- D. Samples:
- 1. Furnish one unit in the color and face pattern
- specified; approved unit may be used in the work.
- 2. 12 inches square or larger piece of geosynthetic
- reinforcing specified.
-
- E. Test Reports: Submit test reports from an independent
- laboratory demonstrating compliance of concrete units
- with reference standards.
- 1. Water absorption and compressive strength tested in
- accordance with ASTM C 140, Sections 6,8, and 9.
-
- 1.7 DELIVERY, STORAGE, AND HANDLING
-
- A. Inspect the materials upon delivery to assure that
- specified products have been received.
-
- B. Deliver and handle materials in manner that will prevent
- damage.
- 1. Store above ground on wood pallets or blocking.
- 2. Remove damaged or otherwise unsuitable material, when
- so determined, from the site.
- 3. Faces of the modular concrete units shall be free of
- chips, cracks and stains.
-
- C. Prevent wet cement, epoxy, excessive mud, etc., from
- coming in contact with the materials.
- NOTE ** Select one of the following Articles or delete both
- Articles if extra materials are not required.
-
- 1.8 EXTRA MATERIALS
-
- A. Furnish Owner with matching replacement units comprising
- 1 percent of those installed on the Project.
-
- B. Furnish Owner with three replacement units identical to
- those installed on the Project.
-
-
- PART 2 PRODUCTS
-
- 2.1 MANUFACTURERS
-
- A. Provide products fabricated under license from Anchor
- Wall Systems, Inc., 6101 Baker Road, Suite 201,
- Minnetonka, MN 55345; ASD. Tel: (800) 473-4452 or (612)
- 933-8855, FAX: (612) 933-8833.
-
- 2.2 MATERIALS
- NOTE ** Delete one of the following two sets of paragraphs
- headed "Modular Concrete Retaining Wall Units."
- The first is for Anchor Vertica and Vertica Pro;
- the second is for Anchor Diamond and Diamond Pro.
-
- A. Modular Concrete Retaining Wall Units: High strength,
- high density concrete units, freeze-thaw resistant with
- top locator providing a 4 degree set back from plane with
- each course.
- NOTE ** Delete one of the following two paragraphs.
- 1. Acceptable Product: "Anchor Vertica Pro Retaining
- Wall Units".
- 2. Acceptable Product: "Anchor Vertica Retaining Wall
- Units".
- 3. Comply with ASTM C 90 except provide minimum
- compressive strength of 3,000 psi and maximum water
- absorption of 7.0 percent.
- 4. Freeze thaw resistance: In accordance with ASTM
- C 666, modified to 50 cycles.
- 5. Provide units that are positively interlocked with
- integral shear connections adequate for design.
- 6. Minimum weight: 100 pounds per square foot of wall
- face, including fill within the units.
- NOTE ** Delete one of the following two paragraphs.
- 7. Minimum exposed face area (Anchor Vertica units):
- 0.94 square feet.
- 8. Minimum exposed face area (Anchor Vertica Pro units):
- 0.94 square feet.
- 9. Provide units whose dimensions do not vary more than
- plus or minus 1/16 inch from that specified, in any
- molded dimension.
- NOTE ** Delete one of the following two paragraphs.
- 10. Face geometry: Beveled.
- 11. Face geometry: Straight.
- NOTE ** Delete one of the following two paragraphs.
- 12. Texture: Smooth.
- 13. Texture: Rockface.
- 14. Color: As selected by Architect from manufacturer's
- standard selections.
-
- B. Modular Concrete Retaining Wall Units: High strength,
- high density concrete units, freeze-thaw resistant.
- NOTE ** Delete one of the following two paragraphs.
- 1. Acceptable Product: "Anchor Diamond Retaining Wall
- Units".
- 2. Acceptable Product: "Anchor Diamond Pro Retaining
- Wall Units".
- 3. Comply with ASTM C 90 except provide minimum
- compressive strength of 3,000 psi and maximum water
- absorption of 7.0 percent.
- 4. Provide units with an integral concrete shear
- connection flange along the lower rear edge.
- NOTE ** Delete one of the following two paragraphs.
- 5. Minimum exposed face area (Anchor Diamond units):
- 0.67 square feet.
- 6. Minimum exposed face area (Anchor Diamond Pro units):
- 0.94 square feet.
- 7. Unit height: Not more than plus or minus 1/16 inch
- variation from that specified.
- NOTE ** Delete one of the following two paragraphs.
- 8. Face geometry: Beveled.
- 9. Face geometry: Straight.
- NOTE ** Delete one of the following two paragraphs.
- 10. Texture: Smooth.
- 11. Texture: Split rock face.
- 12. Color: As selected by Architect from manufacturer's
- standard selections.
-
- C. Geosynthetic Reinforcement: Woven polyester fiber
- geogrid, expanded polyethylene sheet geogrid, or woven
- polypropylene geotextile.
-
- D. Base:
- NOTE ** Delete 2 of the 3 following paragraphs.
- 1. Drainage aggregate.
- 2. Sand, specified in Section _____.
- 3. Concrete, specified in Section 03300.
-
- E. Drainage Aggregate: Free-draining, coarse aggregate
- complying with ASTM 448, size no. 57, 67, 6, 7 or 8.
- NOTE ** Delete the following paragraph if neither Anchor
- Vertica nor Anchor Vertica Pro units are used.
-
- F. Unit Fill: Same materials as drainage aggregate.
- NOTE ** Normally, the project engineer or geotechnical
- consultant determines whether the soil is suitable
- for backfill purposes. Soil types that are not
- suitable for modular retaining walls include USCS
- Classifications CH, OH, MH, OL, PT, and CL soils
- with a Plasticity Index greater than 25.
-
- G. Backfill: On-site soils unless otherwise indicated on
- the drawings; where additional backfill is required,
- submit sample and specifications to project Geotechnical
- Engineer for approval.
- NOTE ** Delete the following paragraph if drain tile is to
- be installed under another specification section.
- For Anchor Diamond, drains are normally required;
- for Anchor Vertica, they may not be.
-
- H. Foundation Drain: Perforated or slotted PVC pipe or
- corrugated HDPE pipe, covered with geotextile filter
- fabric.
-
-
- PART 3 EXECUTION
-
- 3.1 EXAMINATION
-
- A. Examine the areas and conditions under which retaining
- walls are to be erected.
- 1. Notify the Architect in writing of conditions
- detrimental to the proper and timely completion of
- the work.
- 2. Notify the Architect in writing of site conditions
- which may affect wall performance or may require
- reevaluation of wall design.
-
- B. Do not proceed with the work until unsatisfactory
- conditions have been corrected.
-
- 3.2 EXCAVATION
-
- A. Excavate to the lines and grades shown on the drawings.
- Over-excavation will not be compensated for and
- replacement with compacted fill or wall system components
- will be required at Contractor's expense. Take care not
- to disturb base beyond the lines shown.
-
- 3.3 FOUNDATION PREPARATION
-
- A. Excavate as required for footing or base dimension shown
- on the drawings, unless otherwise directed.
-
- B. Obtain the Geotechnical Engineer's approval of subgrade
- to ensure that the actual soil strength meets or exceeds
- that required.
-
- C. Remove soil not meeting the required strength, and
- replace with acceptable material.
-
- D. Fill over-excavated areas with compacted backfill
- material.
- NOTE ** Retain the following paragraph for Vertica.
-
- E. Proof-roll foundation soil prior to fill and geosynthetic
- reinforcement placement.
-
- 3.4 BASE COURSE PREPARATION
- NOTE ** Show base depth and width on the Drawings.
- Standard minimum base thickness is 6 inches. Edit
- the following paragraph, if necessary.
- NOTE **
- NOTE ** At Contractor's option, designs using reduced depth
- of aggregate and 1 to 2 inch concrete toppings may
- be used. Concrete shall be lean, unreinforced and
- a maximum of 2 inches thick. Where a reinforced
- footing is required, place below the frost line.
- Show any such footings on the Drawings.
-
- A. Place granular base materials as indicated on the
- Drawings, but not less than 6 inches thick.
-
- B. Place and compact base materials to the depths and widths
- indicated on the drawings.
-
- C. Place base materials upon undisturbed soils or on
- foundation soils properly backfilled.
-
- D. Compact base material to a level, hard surface on which
- to place the first course of units.
- NOTE ** Edit the following paragraph if required compaction
- differs from 95 percent.
- 1. Compact to 95 percent standard proctor (ASTM D 698).
-
- E. Prepare base materials to ensure complete contact of
- retaining wall unit with base material. Do not allow
- gaps.
-
- 3.5 ERECTION
-
- A. Erect units in accordance with manufacturer's
- recommendations and as specified herein.
-
- B. Place first course of concrete wall units on the prepared
- base material. Check units for level and alignment.
- Ensure that the top of all units in base course are at
- the same elevation.
-
- C. Ensure that concrete wall units are in full contact with
- base.
-
- D. Place concrete wall units side by side for full length of
- wall alignment. Alignment may be done by using a string
- line or offset of wall line.
-
- E. Fill all voids between and within concrete wall units
- with drainage aggregate.
- NOTE ** Delete 1 of the 2 following paragraphs.
- NOTE **
- NOTE ** Anchor Vertica and Anchor Diamond units require 12
- inches of drainage fill.
- NOTE ** Anchor Vertica Pro units may require as little as 6
- inches of drainage fill.
-
- F. Place at least 12 inches of free-draining aggregate
- behind the concrete wall units.
-
- G. Place at least 6 inches of free-draining aggregate behind
- the concrete wall units.
-
- H. Install drain tile at lowest elevation possible to
- maintain gravity flow of water to outside reinforced
- zone. "Daylight" drainage collection pipe to an
- approximate location away from wall system at each low
- point or at 50 foot intervals along wall.
-
- I. Remove excess fill from top of concrete wall units and
- install next course. Ensure that drainage aggregate and
- backfill are compacted before installation of next
- course.
- NOTE ** Delete 1 of the 2 following paragraphs.
- NOTE **
- NOTE ** Retain only the first for Anchor Vertica and Anchor
- Vertica Pro units.
- NOTE ** Retain only the second for Anchor Diamond and
- Anchor Diamond Pro units.
-
- J. Install each succeeding course so the side slots are in
- contact with the locator. Pull the units forward until
- the side slot of the unit touches the back of the locator
- of the previous course.
-
- K. Pull each unit forward as far as possible until the
- locating surface of the unit contacts the locating
- surface of the unit in the preceding course.
-
- L. Backfill as each course is completed.
-
- M. Install geosynthetic reinforcement in accordance with
- retaining wall manufacturer's design recommendations and
- as indicated on drawings.
-
- 3.6 BACKFILL PLACEMENT
-
- A. Place, spread, and compact reinforced backfill in a
- manner to minimize slack in reinforcement.
-
- B. Place and compact fill in the reinforced zone.
- 1. Lifts not exceeding 6 to 8 inches in loose thickness
- where hand-operated compaction equipment is used.
- 2. Lifts not exceeding 12 inches in loose thickness
- where heavy, self-propelled compaction equipment is
- used.
-
- C. Compact fill placed in reinforced zone to minimum 95
- percent of soil's standard Proctor density (per ASTM D
- 698) or as recommended by project Geotechnical Engineer.
-
- D. Allow only lightweight hand-operated equipment within 4
- feet of back of retaining wall units, or one-half the
- wall height, whichever is greater.
- NOTE ** Retain the following Article if applicable.
-
- 3.7 CAP UNIT INSTALLATION
-
- A. Apply construction adhesive to the top surface of the
- unit below and place the cap unit into desired position.
-
- B. Cut cap units if necessary to obtain the proper fit.
-
- C. Backfill and compact to finish grade.
-
- 3.8 FIELD QUALITY CONTROL
-
- A. Retain a qualified independent third party to verify
- correct installation of materials in accordance with
- drawings and these specifications.
-
- B. Owner, at his own expense, may retain a qualified
- professional to perform random quality assurance checks.
-
- C. Correct work found deficient and not in accordance with
- drawings and these specifications.
-
- D. Retaining wall will not be considered complete until
- accepted by Architect or duly appointed representative of
- the Owner.
-
- 3.9 ADJUSTING AND CLEANING
-
- A. Replace damaged units prior to Substantial Completion.
-
- B. Remove debris and scrap from the site.
-
- C. Leave adjacent paved areas broom clean.
-
-
- END OF SECTION
-